🚀 go-pugleaf

I have a couple questions regarding cordless telephones.

    What is the likelihood of another phone operating on the same 
    channel as yours?  Possible concerns include a) others being able to 
    listen in on phone converstions and b) others being able to place 
    calls via your phone line.
    
    Is is possible to disable the base phone to prevent other handsets 
    from dialing out?
    
My parents have just purchased a cordless phone and are concerned about 
unauthorized monitoring or use.  This isn't my area of expertise, but I 
don't want to blow my image.  Any information about cordless phones 
would be appreciated.

BTW, if this is covered in a FAQ list, please point me toward it.